A 3-year-old boy was referred to our hospital for management of Kawasaki disease at 5 days of illness. Echocardiographic examination on admission suggested aneurysmal dilation of the right coronary artery and a possible aorta-left main trunk connection. However, detailed echocardiography at 12 days of illness revealed an abnormal bifurcation of the proximal right coronary artery and no real connection of the aorta-left main trunk, all of which indicated the presence of a single right coronary artery. These diagnoses were confirmed by selective coronary angiography, which was performed later. Considering the difficulties in diagnosing congenital coronary anomalies, which may increase the risk of future fatal events, knowing the disease entity of the congenital coronary arterial anomaly is important for the accurate evaluation of coronary arteries in patients with Kawasaki disease. To the best of our knowledge, this is the first case report of a patient with Kawasaki disease complicated by a single right coronary artery; however, following a search of the literature, we found a brief conference abstract written in Japanese relating to the same clinical condition.
Background: Cardiac dysfunction is one of the vital determinants of long-term outcome in patients with Fontan circulation. However, underlying mechanisms for the development of ventricular dysfunction remain unclear. Energy depletion is a key feature of failing ventricles, and heart failure alters ventricular energy consumption for intracellular Ca2+ handling during excitation-contraction (E-C) coupling. We hypothesized that ventricular energetic efficiency for Ca2+ handling as well as for external work production is reduced in Fontan circulation compared with biventricular circulation.
Method: A pressure-volume (PV) relationship was constructed during cardiac catheterization in 14 Fontan patients and 29 controls with biventricular heart. Myocardial oxygen consumption (MVO2) was estimated by PV area (PVA), and ventricular mechanical efficiency (Ve) was calculated as the ratio of stroke work (SW) and PVA. The fraction of the total amount of Ca2+ recycled by the sarcoplasmic reticulum during E-C coupling, termed recirculation fraction (RF), was computed by fitting the decay of contractile index after rapid atrial pacing to a combined sinusoid and logistic function.
Result: MVO2 was significantly higher (3.2 ± 1.0 vs. 2.6 ± 0.5 mLO2/beat/100g, p < .05), whereas SW was significantly lower in Fontan patients than in controls, indicating higher oxygen cost for ventricular work in Fontan patients. This was consistent with a significantly lower Ve in Fontan patients than in controls (p < .01). Furthermore, oxygen cost for Ca2+ handling was significantly higher in Fontan patients than in controls, as indicated by a lower RF in Fontan patients than in controls (0.66 ± 0.04 vs. 0.77 ± 0.02, p < .05). Importantly, RF was significantly correlated with Ve independent of ventricular contractility and afterload (p < .05).
Conclusion: Higher oxygen cost for E-C coupling in the Fontan ventricle appears to affect the mechanical efficiency. Since RF is known to be independent of catecholamine status, these features of Fontan ventricular energetics can lead to myocardial energy depletion throughout a patient’s life. Strategies involving Ca2+ handling may effectively terminate the vicious cycle of developing ventricular dysfunction in Fontan circulation.
OBJETIVO: A sedação é um passo importante para aliviar e prevenir a recorrência de cianose no manejo de pacientes com crises hipercianóticas associadas à tetralogia de Fallot (T4F). Este relato de caso ilustra a eficácia da sedação induzida por dexmedetomidina no manejo de crises hipercianóticas em um recém-nascido com T4F. DESCRIÇÃO: Um paciente recém-nascido a termo de 8 dias de idade com T4F apresentava crises hipercianóticas, indicadas por quedas abruptas no nível de saturação arterial (SpO2), medido por um oxímetro de pulso, de 80% até 50%, quando o paciente ficava agitado ou irritável. Nós começamos a infusão contínua de dexmedetomidina em uma dosagem de 0,2 µg/kg/min sem injeção de ataque em bolus. Cerca de meia hora depois do início da infusão de dexmedetomidina, o paciente atingiu um nível aceitável de sedação, e sua freqüência cardíaca diminuiu aproximadamente 20 batidas por minuto. Não houve nenhuma depressão respiratória aparente ou mudança acentuada em sua pressão arterial. A SpO2 também continuou estável durante a infusão de dexmedetomidina. No dia seguinte à sua hospitalização, o paciente passou com sucesso por uma operação de anastomose de Blalock-Taussig. COMENTÁRIOS: A dexmedetomidina pode ser útil no manejo de crises hipercianóticas em pacientes pediátricos com T4F.
